Facebook may acquire Norwegian browser maker Opera Software, developer of the Opera and Opera Mini browsers for desktops and mobile phones, according to a report.

The purchase of Opera would give Facebook a way to quickly create a dedicated browser customized for the social networking giant and its estimated 900 million active monthly users.

It would also put Facebook in the middle of a browser battle with Microsoft (Internet Explorer), Mozilla (Firefox), Google (Chrome) and Apple (Safari). Some of those companies -- like Microsoft -- have partnered with Facebook, while others -- such as Google -- compete in the social networking space.

U.K.-based technology website Pocket-lint first reported Friday that Facebook "is looking to buy Opera Software," citing an unnamed source it described only as "trusted." Other sites, including The Next Web, claimed that while their sources could not verify Facebook's interest, they did say Opera's management has been talking to potential suitors.

Both Opera and Facebook declined to comment on Pocket-lint's report.

Opera is really the only top-five browser that Facebook, or anyone for that matter, could conceivably acquire.

Three of the five are locked into operating systems: Internet Explorer, with Windows; Chrome, with ChromeOS; and Safari, with OS X and iOS.

And Firefox, while not associated with an OS maker, is backed by the non-profit Mozilla Foundation, which has used the "open Web" mantra since its inception. It's hard to believe that Mozilla would sell Firefox to Facebook, a company that has reaped billions from a self-contained ecosystem.

That leaves only Opera.

But while Opera is the one viable deal Facebook could make, the Norwegian browser comes with its own baggage: It's the fifth browser, and a distant fifth at that, in a five-browser market.

Last month, Opera accounted for just 1.6% of the world's in-use browsers, according to data from metrics company Net Applications. Opera has never cracked the 3% mark, never been in anything but fifth place on the desktop. Even No. 4 Safari has three times Opera's usage share.

And on mobile, the numbers are little better.

Even though Opera claims about 210 million Opera Mini users worldwide, Net Applications pegged the browser's share of mobile at 12% for April, just half what it was a year earlier. Most of Opera Mini's losses have gone to Apple's Safari, the default browser on the iPhone and iPad, whose owners have a voracious appetite for the Web.

That's not to say that a Facebook-owned Opera and Opera Mini wouldn't change those numbers: In the U.S., Facebook collects about one-in-every-five page views. If Facebook branded Opera and Opera Mini with its own nameplate and pitched them to its members, it could quickly boost the browsers' shares.

Opera Mini also has an edge that could play to Facebook's advantage: Apple refuses to allow third-party browsers not built atop Safari into the App Store.

But Opera Mini is already in the iOS App Store, managing that feat because it really isn't a browser, at least as Apple defines one. Rather than render HTML locally on the device, Opera Mini is essentially a proxy that shuttles page requests to Opera's own servers, which render the page, then aggressively compress it before sending it back to the device.

Opera's not-quite-a-browser has been in the App Store for more than two years, and is also available for Android, Symbian-powered phones and BlackBerry. Opera has not created a version of Mini for Microsoft's Windows Phone, or committed to developing a Metro app for the upcoming Windows 8 or Windows RT, however.

Opera Mini would let Facebook present the social network in a more browser-like interface than the Facebook app on iOS. Spooked by the relative paucity of ads on its mobile apps, Facebook may see Opera Mini as a way to show the traditional display ads that have been its primary money maker.

Facebook's app has also been bashed for being slow, another reason Opera Mini could be a good fit for the firm. Opera boasts that its servers compress Web page data by as much as 90%, resulting in faster delivery to the device, especially on slower connections.

Opera's infrastructure might be overwhelmed by Facebook's traffic, but the company has been beefing up its servers, according to its most recent financial statements. In the first quarter, Opera spent $2 million on infrastructure, a 66% increase over the same quarter the year before.

Other parts of Opera would also be attractive to a buyer like Facebook, including Opera's three mobile ad networks -- two acquired last February -- the company's new payment processing technology, dubbed "Opera Payment Exchange;" and its existing relationships with scores of carriers and handset makers.

And Opera's revenues are on an upswing.

First quarter revenue was $47 million, up 28% from the same period in 2011, with the biggest share -- nearly $17 million, or 36% of the total -- coming from the search deals Opera has with Google, Yandex in Russia, and Baidu in China for its desktop browser. Like rival Mozilla's Firefox, Opera generates most of its search income from Google.

Facebook's interest in Opera may be only speculation, but the company's pursuit of a browser has been discussed for much longer, usually with the expectation of the company building its own from scratch. In 2008, for example, Facebook hired Mike Schroepfer, then Mozilla's vice president of engineering, a driving force behind Firefox, to take the same title at the social network.